Closing the gaps: testing the efficacy of carbapenem and cephalosporins in treating late-stage anthrax

Anthrax is a fatal zoonotic disease caused by exposure to Bacillus anthracis spores. The CDC in its guidelines divides anthrax treatment to three indications according to disease progression: PEP, systemic, systemic with suspicion of CNS infection. While prognosis of PEP or early treatment of systemic anthrax is very good, ingress of the bacteria into the CNS possesses a substantial clinical challenge. Here we use rabbits to test the efficacy of the combined treatment of Meropenem and Doxycycline which is the first choice in the CDC recommendations for treating systemic patients with indication of CNS infection. In addition, we test the efficacy of the first-generation cepha-losporin, cefazolin, in treating different stages of the disease. We found that the combination of Doxycycline and Meropenem is highly effective in treating rabbits in our inhalation model. Cefazoline was efficient only as PEP or systemic stage treatment but not CNS infected animals. Our findings support the CDC recommendation of using a combination of Doxycycline and Mero-penem for systemic patients with or without indications for CNS infection. We found that Cefazoline is a decent choice for PEP or early sage systemic disease but recommend considering using this antibiotic only if all other options are not available.